Improvement in lifting-jacks



UNITED STATES PATENT OFFICE.

THOMAS J. JENNE, OF GOU VERNEIIR, NEW YORK.

lMPROVEMENT m LlFTlNG-JACKS.

Specification forming part of Letters Patent No. 192,831, dated July 10, 1877; application filed May 28, 1877.

To all whom it may concern:

Be it known that I, THOMAS J. JENNE, of Gouverneur, in the county of St. Lawrence and State of New York,have invented certain new and useful Improvements in Lifting-Jacks, of which the following is a specification: p

This invention relates to certain improvements in that class of lifting apparatus in which the lifting-bar is operated by frictionpawls and a lever.

My invention consists in a hook suspended from the frame of the apparatus and provided at its lower end with a pin, which forms the fulcrum of the lever that carries the loops for operating the friction-pawls on the lifting-bar, the said fulcrum-pin being prolonged and constructedat its end with an eye or loop, through which thelifting-bar is passed, and bywhich loop or eye it is guided in its vertical movement, all of which will be fully hereinafter described.

In the drawings, Figs. 1 and 2 represent perspective views of my invention, and Fig. 3 a

detached view, showing two friction-pawls.

The letter A represents a suitable standard.

or frame, for supporting the various parts of the apparatus. B represents the lifting-bar, upon which are fitted two loosely sliding pawls, G G,'with hooks at their ends, which engage in the loops D D, attached to the lever E, at each side of its fulcrum F. The lever is suspended by a hook, G, from the upper part of the support A, and is provided with a suitable handle, by means of which it may be operated. The pin forming the fulcrum F of said lever is prolonged in front and formed into a loop, through which the lifting-bar extends, said loop forming a guide for the same. The lower end of the lifting-bar has a hook or step formed thereon, which serves to take 4 hold of the object to be lifted.

The operation of the apparatus is as follows Upon giving a reciprocating motion to the lever, the friction-pawls will be alternately lifted and depressed. Each pawl, as lifted, will be tilted in such position as to gripe the bar firmly and lift it with it, and on being depressed will slide loosely back to its former position. As the levers are lifted alternately, the bar will be raised at each motion of the lever, aswill be evident.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, is-- The hook G, suspendedfrom the frame A,

and provided with the pin forming the ful- 0mm of the lever, said fulcrumpin being constructed'with a loop or eye at its end,through which the, lifting-bar passes, in combination with the loops D D connected with the lever on opposite sides of its fulcrum, and the pawls O G arranged on the lifting-bar, the' whole being constructed and arranged to operate substantially as and for the purpose specified. In testimony that I claim the foregoing, I have hereunto set my hand.

THOMAS J. JENNE.

Witnesses:

J. B. STAMAUR, A. H. NORRIS. 

